Caribbean Low to Organize?

In the southwestern Caribbean, the area of low pressure I have been watching continues to make ever so slow progress in organizing. As of about 5pm ET, the low had a pressure of 1007mb and that may have risen a little bit since then. The center is about 200 miles NE of Bluefields Nicaragua, but this and the central pressure come with a moderate level of uncertainty. The low-level center is very disorganized and has gotten harder to find in the last few hours. Winds are very light in the area as well. Hurricane Hunters may explore this area on Saturday if necessary, but until then we only have satellite and surface observations to work with.

Overall conditions that favor cyclogenesis have gotten better over the last day or so, and will continue improve. There are a lot of little things that are inhibiting growth, mainly in the convection department. Vorticity, the spin in the atmosphere associated with cyclones, is strong and is strengthening with time. Mid and upper level shear is taking most of the convection off to the east and northeast towards the Greater Antilles. A weak and lopsided upper level anticyclone, which fans the top of healthy cyclones, is centered to the east of the surface low pressure system. This has opened up a small area of shearless atmosphere. If this anticyclone can grow and organize, the condition of the surface low will improve.

Sea surface temperatures are plenty warm for development, but they need to be watched as this low meanders over the Caribbean with nonexistent steering currents. If cyclones sit over water for too long it drains the ocean’s heat and energy, cooling the water. This can weaken cyclones sometimes.

As for possible track, we really will not know until steering currents can pick up and the system starts to move. I expect a lot of wandering around for the next few days. Beyond the weekend we may see a more northerly component, but again exact movement is not known at this time.

All in all, expect a lot of slow progress for this system both in intensity and track. Stay tuned for more. Please go to the National Hurricane Center at hurricanes.gov or find them on facebook for the latest official information.

Meteorology Mumbo!

Eyewall Replacement Cycle -- As strong hurricanes, typhoons, or cyclones intensify or hold steady, they can often replace the strongest region of winds and heaviest rains called the eyewall. This happens, usually in major hurricanes, when subsidence begins or intensifies outside of the eyewall OR a stronger band of storms forms outside of the main eyewall and feeds into the center of the system. Generally the effect is a weakening of the system at least temporarily. The hurricane also usually expands during this process. Cycles typically last 12-18 hours including the contraction process. The inner eyewall may dissipated in less than 12 hours after the outer eyewall forms.

Forecast Disclaimer

Any forecast that I make and post here or anywhere else is NOT an official forecast and should not be used as such. They are just my opinion, and should be used as such. For official forecasts and information please go to the National Hurricane Center at hurricanes.gov or your local National Weather Service at weather.gov.